Health Benefits Module

The Health Benefits Module is based on the Air Quality Benefits Assessment Tool (AQBAT) developed by Health Canada (Judek et al., 2012). The module starts by calculating the Baseline Counts (bch) for the pre-determined 18 health endpoints used in AQBAT and which are shown in the table below.

HID Health Endpoint h Pollutant Age
1Acute Exposure MortalityO3, SO2, NOXAll
2Acute Respiratory Symptom DaysAcute PM25, O3All
3Adult Chronic Bronchitis CasesChronic PM2525+
4Asthma Symptom DaysAcute PM25, O3All
5Cardiac Emergency Room VisitsAcute PM25All
6Cardiac Hospital AdmissionsAcute PM25All
7Child Acute Bronchitis EpisodesChronic PM25Under 20
8Chronic Exposure MortalityChronic PM2530+
9Elderly Cardiac Hospital AdmissionsCO65+
10Minor Restricted Activity DaysO3All
11Respiratory Emergency Room VisitsAcute PM25, O3All
12Respiratory Hospital AdmissionsAcute PM25, O3All
13Restricted Activity DaysAcute PM2520+
14Chronic Exposure Cardiovascular MortalityChronic PM2530+
15Chronic Exposure Respiratory MortalityChronic PM25, O330+
16Chronic Exposure Cerebrovascular MortalityChronic PM2530+
17Chronic Exposure Ischemic Heart Disease MortalityChronic PM2530+
18Chronic Exposure Lung Cancer MortalityChronic PM2530+

bch is calculated as the product of the rgi|h values and population size Kgi estimated by SMARTPLANS in each zone i, and then summed over all zones. The result is a vector of 18 bch values for the 18 health endpoints:

Next, pollution concentrations for pollutants p are obtained from the estimates generated by the Pollution Concentration Models for both the base case scenario r and alternative scenario a to calculate the average region-wide concentration Cp|r and Cp|a per pollutant p. The module then calculates the Concentration Risk Functions (CRFs) for pollutant p and health endpoint h as the percent excess (PctXShp) based on the calculated average concentrations. The CRF is formulated as either a linear or a Poisson function. If the CRF is linear, then:

On the other hand, if the CRF is Poisson, then:

where ω is the threshold per each pollutant and βCRF are the parameters for each health endpoint specified above.

The Health Benefit Module then calculates the life years gained (LYGhp) by using the slope values θhp:

The gross count (GChp) per pollutant p and corresponding health endpoints h for the following pollutants (PM2.5Chronic, PM2.5Acute, O3, SO2, NOx, and CO) are calculated as follows:

where αp is a pollution adjustment factor set to 0.4192 for O3 and 1 for all other pollutants. To avoid double counting, GChp values are adjusted for the health endpoints that overlaps with multiple pollutants. That is:

where h' and p' pertain to health endpoints and pollutants that overlap with health endpoints h and pollutants p.

The Netted Counts (NC) are then calculated as follows:

Lastly, the Dollar Valuation (DVhp) for the net count is estimated as follows:

where ρ is the monetary conversion factor value.



Judek, S., Stieb, D., Jovic, B., Edwards, B., 2012. Air Quality Benefits Assessment Tool (AQBAT) - User Guide. Health Canada - Healthy Environments and Consumer Safety Branch.