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PROCESSING NAPS DETAILS              

DENE BOWDALO, Updated 29th April 2018

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PROCESSING NOTES

*Downloaded Stations2017_v3.xlsx excel file and exported first metadata sheet, to 
NAPS_META.csv

*Received missing 1976 files for O3, NO2 and CO, and missing NO 1999 file from 
ec.info-donnees-rnspa-naps-data-info.ec@canada.ca 

*Removed special characters from last lines in some of the annual data files which breaks
reading

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NETWORK DESCRIPTION

The goal of the National Air Pollution Surveillance (NAPS) program is to provide accurate 
and long-term air quality data of a uniform standard across Canada. NAPS was established 
in 1969 to monitor and assess the quality of ambient (outdoor) air in the populated 
regions of Canada. NAPS is managed using a cooperative agreement among the provinces, 
territories and some municipal governments. In 1969, eight provinces -- Nova Scotia, 
New Brunswick, Quebec, Ontario, Manitoba, Saskatchewan, Alberta and British Columbia -- 
joined the program. In the first annual data report 36 monitoring sites reported to the 
Canada-wide database. Today there are 286 sites in 203 communities located in every 
province and territory.

NAPS produced its first annual summary in 1972, reporting on measurements of sulphur 
dioxide and particulate matter. Today sulphur dioxide, nitrogen dioxide, ozone, fine 
particulate matter and carbon monoxide are continuously monitored. These measurements are 
used by the provinces to report the Air Quality Index (AQI) and by Environment Canada to 
report the Air Quality Health Index (AQHI).

The methods used by NAPS to measure air quality have evolved over the years. Additional 
measurements of a variety of new substances were initiated in the 1980s. Air samples for 
the additional substances are collected at regular frequencies by NAPS for later analysis 
at Environment Canada chemistry labs in Ottawa. Various techniques are used to analyze 
these samples for more than 340 types of chemicals at typical urban NAPS sites. For 
example, air collected in canisters is analyzed for more than 167 volatile organic 
compounds that contribute to smog formation. These compounds, such as benzene, are 
released into the air by motor vehicles, industrial processes and fuel-handling 
operations. Filter media and foam plugs are used to collect air samples that are analyzed 
for chemical contaminants that are harmful to human health and the environment.

DESCRIPTION URL: https://www.canada.ca/en/environment-climate-change/services/
                 air-pollution/monitoring-networks-data/national-air-pollution
                 -program.html
     
DATA ACCESS URL: http://maps-cartes.ec.gc.ca/rnspa-naps/data.aspx
   
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QUALITY ASSESSMENT LEVEL 

Not Stated

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CONTACT

NAPS Manager, Analysis and Air Quality Section, Environment Canada, 335 River Road, 
Ottawa ON  K1A 0H3
Rnspa-napsinfo@ec.gc.ca

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AVAIALABLE SPECIES (DATA LAST ACCESSED: 26TH APRIL)

Ozone (1974-2017)
Nitric Oxide (1980-2017)
Nitrogen Dioxide (1974-2017)
Carbon Monoxide (1974-2017)
Isoprene (1989-2017)

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FORMAT

Ozone, Nitric Oxide, Nitrogen Dioxide and Carbon Monoxide
The data files are single annual space formatted .hly files, including all sites, for a 
single species

Each row gives 24 hourly (1 day) measurements at one site, for a single species

Metadata is given originally in an external excel spreadsheet: Stations2017_v3.xlsx 
(converted to csv), with data for each site per line

Isoprene
Data files are annual Excel XLS files, in separate specific files for different sites. 
Each row details the measurements of different VOCs for a specific analysed canister gas 
sample. The date, start time and sample lengths are all given row by row.

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METADATA/DETAIL FILES

CORE
NAPS_META.csv

OTHER
NAPS_Integrated_Data_Format_VOC_FROM2017.pdf  
NAPS-pollutant-codesV2014.xlsx  
Stations2017_v3.xlsx
10_years_NAPS_report_2013.pdf
NAPS_QUALITY_ASSURANCE_2004.pdf
VOC_METADATA.xls
VOC_Detection_Level.xls

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DATAFILE VARIABLES

Ozone, Nitric Oxide, Nitrogen Dioxide and Carbon Monoxide:

Not explicitly given as column names, but each line in datafile is structured as follows:

pollutant code	     length of field:3	 (005=carbon monoxide, 006=nitrogen dioxide,
                                          007=ozone, 008=nitric oxide , 78-79-5=isoprene) 
station (NAPS id)	 length of field:6
Year	             length of field:4
Month                length of field:2
Day	                 length of field:2
average for day	     length of field:4
minimum for day	     length of field:4
maximum for day      length of field:4
hourly reading 1     length of field:4
hourly reading 2	 length of field:4
hourly reading 3	 length of field:4
hourly reading 4	 length of field:4
hourly reading 5     length of field:4
hourly reading 6	 length of field:4
hourly reading 7	 length of field:4
hourly reading 8	 length of field:4
hourly reading 9	 length of field:4
hourly reading 10	 length of field:4
hourly reading 11	 length of field:4
hourly reading 12	 length of field:4
hourly reading 13	 length of field:4
hourly reading 14	 length of field:4
hourly reading 15	 length of field:4
hourly reading 16    length of field:4
hourly reading 17	 length of field:4
hourly reading 18	 length of field:4
hourly reading 19	 length of field:4
hourly reading 20	 length of field:4
hourly reading 21	 length of field:4
hourly reading 22	 length of field:4
hourly reading 23	 length of field:4
hourly reading 24	 length of field:4

Isoprene (and other VOCs):

Compounds - Under this column are the sample dates (local time)
Ethane
Ethylene
Acetylene
Propylene
Propane
1-Propyne
Isobutane
1-Butene/Isobutene
1,3-Butadiene
Butane
trans-2-Butene
2,2-Dimethylpropane
1-Butyne
cis-2-Butene
Isopentane
1-Pentene
2-Methyl-1-Pentene
2-Methyl-1-butene
3-Methyl-1-butene
Pentane
Isoprene
trans-2-Pentene
cis-2-Pentene
2-Methyl-2-butene
2,2-Dimethylbutane
Cyclopentene
4-Methyl-1-pentene
3-Methyl-1-pentene
Cyclopentane
2,3-Dimethylbutane
trans-4-Methyl-2-pentene
2-Methylpentane
cis-4-Methyl-2-pentene
3-Methylpentane
1-Hexene
Hexane
trans-2-Hexene
2-methyl-2-Pentene
2-Ethyl-1-Butene
trans-3-Methyl-2-pentene
cis-2-Hexene
cis-3-Methyl-2-pentene
2,2-Dimethylpentane
Methylcyclopentane
2,4-Dimethylpentane
2,2,3-Trimethylbutane
1-Methylcyclopentene
Benzene
Cyclohexane
2-Methylhexane
2,3-Dimethylpentane
Cyclohexene
3-Methylhexane
1-Heptene
2,2,4-Trimethylpentane
trans-3-Heptene
cis-3-Heptene
Heptane
trans-2-Heptene
cis-2-Heptene
2,2-Dimethylhexane
Methylcyclohexane
2,5-Dimethylhexane
2,4-Dimethylhexane
2,3,4-Trimethylpentane
Toluene
2-Methylheptane
1-Methylcyclohexene
4-Methylheptane
3-Methylheptane
cis-1,3-Dimethylcyclohexane
trans-1,4-Dimethylcyclohexane
2,2,5-Trimethylhexane
1-Octene
Octane
trans-1,2-Dimethylcyclohexane
trans-2-Octene
cis-1,4/t-1,3-Dimethylcyclohexane
cis-2-Octene
cis-1,2-Dimethylcyclohexane
Ethylbenzene
2,5-Dimethylheptane
m and p-Xylene
4-Methyloctane
3-Methyloctane
Styrene
o-Xylene
1-Nonene
Nonane
iso-Propylbenzene
3,6-Dimethyloctane
n-Propylbenzene
3-Ethyltoluene
4-Ethyltoluene
1,3,5-Trimethylbenzene
2-Ethyltoluene;1-Decene
tert-Butylbenzene
1,2,4-Trimethylbenzene
Decane;iso-Butylbenzene
sec-Butylbenzene
1,2,3-Trimethylbenzene
p-Cymene
Indane
1-Undecene
1,3-Diethylbenzene
1,4-Diethylbenzene
n-Butylbenzene
1,2-Diethylbenzene
Undecane
Naphthalene
Dodecane
Hexylbenzene
MTBE
a-Pinene
b-Pinene
d-Limonene
Camphene
Freon22
Chloromethane
Freon114
Freon113
Vinylchloride
Bromomethane
Chloroethane
Freon11
Freon12
Ethylbromide
1,1-Dichloroethylene
Dichloromethane
trans-1,2-Dichloroethylene
1,1-Dichloroethane
cis-1,2-Dichloroethylene
Bromochloromethane
Chloroform
1,2-Dichloroethane
1,1,1-Trichloroethane
Carbontetrachloride
Dibromomethane
1,2-Dichloropropane
Bromodichloromethane
Trichloroethylene
cis-1,3-Dichloropropene
trans-1,3-Dichloropropene
1,1,2-Trichloroethane
Bromotrichloromethane
Dibromochloromethane
EDB;Tetrachloroethylene
Chlorobenzene
Benzylchloride
Bromoform
1,4-Dichlorobutane
1,1,2,2-Tetrachloroethane
1,3-Dichlorobenzene
1,4-Dichlorobenzene
1,2-Dichlorobenzene
1,2,4-Trichlorobenzene
Hexachlorobutadiene
Formaldehyde
Acetaldehyde
Acrolein
Acetone
Propionaldehyde
Crotonaldehyde
MEK
Benzaldehyde
2-Pentanone/Isovaleraldehyde
Valeraldehyde
o-Tolualdehyde
m-Tolualdehyde
p-Tolualdehyde
MIBK
Hexanal
2,5-Dimethylbenzaldehyde
Sample ID#
Sample Date - sample date (local time)
Canister ID#
Sample Volume - sample volume (metres cubed)
NAPS ID
START TIME - start time of sample (local time)
DURATION - duration of sample (in hours)


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METADATA VARIABLES

NAPS_ID
STATION_NAME
STATUS
STREET_ADDRESS
CITY
PROVINCE
Postal_Code
TimeZone
Lat_Decimal
Long_Decimal
Elevation_m
StartYear
EndYear
INTAKE_HEIGHT_m
DESIGNATED
SO2
CO
NO2
NO
NOX
O3
PM_10_continuous
PM_25_015_continuous
PM_25_017_dryer
PM_25_018_BAM_RH45
PM_25_022__FDMS
PM_1_GRIMM180
PM_25_026_GRIMM180
PM_10_GRIMM180
PM_25_030_BAM_RH3
PM_10_031_BAM_RH35
PM_25_032_SHARP
Hg
BTEX
UFP
H2S
THC
TRS
BC
NH3
VOC
Carbonyl
SPECIATION
PM_25_DICHOTorPARTISOL
PM_INTEGRATED
PM10-2.5
PM2.5 RM
DICHOTX_METALS
PAH
Integrated_Msrmt
S_Type
Urban_C
Pop4km_C
LU400m_C
Combined_Stations
NAPS_C
SCALE
Population Ctr
CENSUS_DIVISION
CENSUS_SUBDIVISION
CENSUS_AGGLOMERATION/ METROPOLITAN_AREA
AirShed
CoreSite

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UNITS (Source: NAPS-pollutant-codesV2014.xlsx)

Ozone             ppbv 
Nitric Oxide      ppbv
Nitrogen Dioxide  ppbv
Carbon Monoxide   ppmv
Isoprene          μg/m3

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UNIT PRECISION (Source: NAPS-pollutant-codesV2014.xlsx)

Ozone             1.0 ppbv 
Nitric Oxide      1.0 ppbv
Nitrogen Dioxide  1.0 ppbv
Carbon Monoxide   0.1 ppmv
Isoprene          Not Given

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LIMIT OF DETECTION (Source: 10_years_NAPS_report_2013.pdf, VOC_Detection_Level.xls)

**Defined as twice the zero noise level by the US EPA - and is typically reported as such

Ozone             1.0  ppbv 
Nitric Oxide      1.0  ppbv
Nitrogen Dioxide  1.0  ppbv
Carbon Monoxide   0.1  ppmv
Isoprene          0.023 or 0.05 μg/m3 **0.05μg/m3 given as general figure for organic 
                                      compounds in 10_years_NAPS_report_2013.pdf, specific 
                                      LOD of 0.023μg/m3 for isoprene given in 
                                      VOC_Detection_Level.xls

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REPRESENTIVITY (Source: Stations2017_v3.xlsx)

SITE TYPES (S_Type):
PE - General Population Exposure (Site lcoated in an urban area where populations live, 
     work, shop, play, and that are not classified as transportation or point sources) 

RB - Regional Background (Site outside urban area)

T  - Transportation Source Influenced (Site within 100m  of a major road (defined as all 
freeways, highways, and arterial and collector roads with an Annual Average Daily Traffic 
(AADT > 15,000), or influenced by off-road vehicles and engines, rail, marine, or aviation 
sources located in an urban area.

PS - Point Source Influenced (Site near (<~10 km) of a major stationary emissions source 
located in an urban area; classification based on VOC and SO2 (>~1,000 tonnes/yr.)
measurement data)

LOCAL LAND USE CLASSIFICATION (LU400m_C) (Given as: Dominant within 400 m radius) 
A - Agricultural
C - Commercial
F - Forested
I - Industrial
O - Open 
P - Parks
R - Residential 
W - Water

LEVELS OF URBANISATION (Urban_C):
LU - Large Urban Area, Large population centre (population >=100,000)
MU - Medium Urban Area, Medium population centre (population between 30,000 - 99,999)
SU - Small Urban Area, Small population centre (population between 1,000 - 29,999)
NU - Non-Urban Area, Non-urban area (population < 1,000)

NEIGHBOURHOOD POPULATION (Pop4km_C) (Given as: Categories of residential population within 
                                     4 km of monitor)
P1 - < 500
P2 - 500-9,999
P3 - 10,000-49,999
P4 - 50,000-99,999
P5 - 100,000-149,999
P6 - >= 150,000

SCALE OF REPRESENTATIVENESS (SCALE)

To clarify the nature of the link between general monitoring objectives, site types, and 
the physical location of a particular monitor, the concept of spatial representativeness 
is defined. The goal in locating monitors is to correctly match the spatial scale 
represented by the sample of monitored air with the spatial scale most appropriate for the 
monitoring site type, air pollutant to be measured, and the monitoring objective. Thus 
spatial scale of representativeness is described in terms of the physical dimensions of 
the air parcel nearest to a monitoring site throughout which actual pollutant 
concentrations are reasonably similar. The scales of representativeness of most interest 
for air quality monitoring are described as follows:

MI - Micro (several metres - ~100m)
MD - Middle (~100m - 0.5km, several city blocks) 
NE - Neighbourhood (0.5km - 4km, some extended area of city that has relatively uniform 
                    land use)
SR - Sub-Regional (4km - 50km, city like dimensions. 
R  - Regional (50km - 100s km, rural area of reasonably homogeneous geography, without 
               large sources)
               
**Classifications are really pollutant specific but have been applied to sites primarily 
based on their proximity to roadways

**Neighbourhood and Sub-regional have potential to overlap in applications that concern 
secondarily formed or homogeneously distributed air pollutants

TERRAIN
None Given

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MEASUREMENT METHODLOGIES (Source: 10_years_NAPS_report_2013.pdf)

Ozone - continuous (1 hour average), ultraviolet photometry 

Nitric Oxide - continuous (1 hour average), chemiluminescence

Nitrogen Dioxide - continuous (1 hour average), chemiluminescence (conversion-molybdenum) 
**Use of Molybdenum converters not explicitly stated but implied in 
10_years_NAPS_report_2013.pdf: "NO2 is measured by reducing it to NO using a catalytic 
converter. Converters used in conventional instruments convert some portion of other 
nitrogen species to NO, as well as converting NO2. The amount of interference caused by 
this conversion is more important at rural sites, but there are few rural NO2 sites in the 
network." 

Carbon Monoxide - continuous (1 hour average), non-dispersive infrared spectroscopy

Isoprene - Manual (typically 24-hour samples, but varies, can be as frequent as hourly), 
gas chromatography mass spectrometry

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INSTRUMENT NAME/MODEL NUMBERS

None given

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NETWORK DATA FLAGS (WITH PERSONAL ACCEPTANCE CODES)        *A*=ACCEPTED   *N*=NOT ACCEPTED

No Flags Given before 2017

---------------
NAPS_Integrated_Data_Format_VOC_FROM2017.pdf suggests VOCs from 2017 will have data flags:

V0   Valid value *A*

V1   Valid value - below detection limit *N*

V2   Valid value - extreme or unusual value assessed and considered valid *A*

H1   Historical data that have not been assessed or validated (data prior to 2015) *A*

M1   Missing value - no value available *N*

M2   Missing value - invalidated *N*


MISSING DATA FILL = -999 

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EXTRA DETAILS

Ozone Measurements
O3 measurements are carried out using gas analyzers that operate on the UV light 
absorption principle. All O3 measurements in Canada are ultimately referenced to a 
National Institute of Standards and Technology (NIST) primary UV calibration device. As of 
2008, there were 205 O3 monitoring sites reporting data to the Canada-wide database, 
including 16 CAPMoN regional-scale O3 sites. Measurements are made year-round.

Nitrogen Oxide (NO, NO2, NOX) Measurements
There were 152 sites reporting NO2, NO and NOX data in 2008. Some agencies report only NO 
and NO2 and not NOX. All measurements are made with analyzers operating on the principle 
of chemiluminescence involving the gas phase reaction of NO with O3. Since these analyzers 
only measure NO directly, NO2 is measured by reducing it to NO using a catalytic 
converter. Converters used in conventional instruments convert some portion of other 
nitrogen species to NO, as well as converting NO2. The amount of interference caused by 
this conversion is more important at rural sites, but there are few rural NO2 sites in the 
network.

Carbon Monoxide Measurements 
Continuous CO measurements were made at 74 urban sites in the NAPS network in 2008 using 
Nondispersive Infrared (NDIR) photometry with Gas Filter Correlation (GFC) wheel.

VOC Measurements
OC sampling was carried out at 42 urban monitoring sites in 2008. Samples are usually 
collected over 24-hr periods once every six days and analyzed for more than 100 different 
C2 to C12 hydrocarbons and 40 chlorinated hydrocarbons. VOC measurements are also made at 
13 rural sites and at these sites samples are collected over 4-h sampling periods 
(12:00-16:00) to capture the well-mixed atmosphere and avoid local site influences during 
night-time.

Ambient air samples are collected in 6-L or 3.2-L stainless steel SummaTM polished 
canisters. The canisters are cleaned and evacuated before shipment to the sampling sites. 
In the field, samples are collected using whole air samplers and are shipped back to the 
laboratory under pressure. A combined gas chromatography/flame ionization detector 
(GC/FID) system is used for quantification of C2 hydrocarbons, while a combined gas 
chromatography/mass selective detector (GC/MSD) system is used for quantification of C3 to 
C12 hydrocarbons and chlorinated hydrocarbons. Carbonyl measurements are also made at a 
number of sites using DNPH coated silica gel cartridges with subsequent analysis by high 
pressure liquid chromatography (HPLC).

Zero values are contained and should be treated as values below detection 
(VOC_METADATA.xls)

Site Selection
The selection of sites for the NAPS network is done in consultation with network agencies 
to meet the network objective of producing air quality data representative for the 
geographic area of interest. The sites in the network are selected based on the 
requirements for distribution, location, separation and spatial scale of 
representativeness. They are generally selected to represent where the population lives, 
plays and works. Air monitoring stations at these sites are meant to measure air quality 
trends over the long term and therefore are intended to have some degree of permanency. 
There are also stations established to characterize long range transport and 
trans-boundary movement of air pollutants.

Depending on the specific reasons and purpose for monitoring, some or all of the air 
quality criteria pollutants may be monitored. Some stations are used by jurisdictions for 
air quality index (AQI) reporting, other stations are used for CWS achievement 
determination or for trans-boundary transport monitoring or for special studies of local 
air pollution problems. Some of the stations are air pollution oriented but not 
source-specific oriented. The goal is to provide the best assessment of the air quality or 
of an air pollution problem, for the general population, with the most efficiency.

Quality Assurance 
The Quality Assurance Laboratory provides technical services and expert guidance that both 
support and augment the Quality Assurance programs established by NAPS operating agencies. 
This laboratory certifies and supplies gas mixtures for calibration of sulphur dioxide, 
nitric oxide and carbon monoxide monitors throughout the NAPS network; audits, calibrates 
and certifies agency equipment used to perform these calibrations; and maintains the NAPS 
program’s reference standards for flow, temperature, and pressure measurement, as well as 
a Standard Reference Photometer for measurement of ambient-level ozone concentration. 
Calibration gas component concentrations are certified against internationally-accepted 
Standard Reference Materials, and traceability of NAPS program reference standards to 
national standards is maintained on a biennial basis. The certification services provided 
by the NAPS Quality Assurance laboratory ensure that data collected from NAPS network 
monitors and samplers are of good and uniform quality, and are traceable to SI base units 
of measurement. Laboratory staff also plan and coordinate an interagency proficiency 
testing program for gas concentration measurement, and conduct field audits at NAPS 
network stations across Canada.  Audits are used to assess the performance of NAPS 
monitors and samplers against established quality assurance criteria, and to assess NAPS 
agency conformance to program guidelines for station and monitor siting, station 
operation, and safety.

Accredited Methods for Trace Measurement Analysis
The Science and Technology Branch analytical laboratories at 335 River Road, Ottawa 
provide specialized scientific support and undertakes research and development for 
Environment Canada programs. These S&T labs focus on four main areas: technologies for 
measuring air pollutants in ambient air and from mobile and stationary sources; analysis 
of a wide variety of organic and inorganic compounds in diverse samples; assessments and 
clean-up of contaminated sites; and prevention of and response to pollution emergencies 
such as oil and chemical spills.

The S&T labs at 335 River Road are accredited as conforming to the ISO/IEC 17025:2005 
international standard for laboratory quality assurance. This accreditation is provided 
through the Canadian Association for Laboratory Accreditation (Canadian Association for 
Laboratory Accreditation(CALA)). The current scope of accreditation includes 44 analytical 
tests documented in 42 separate test methods.

