1. Benefits and Costs of Reducing Premature Mortality with Improved Particle Filtration in Buildings
William Fisk and Rengie Chan
Indoor Environment Group
Lawrence Berkeley National Laboratory
Analysis supported by U.S. EPA, Office of Radiation and Indoor Air, Indoor Environments Division

2. Background: Known Health Effects of Outdoor Air Particles (examples)
Premature death in people with heart or lung disease
Nonfatal heart attacks
Aggravated asthma
Decreased lung function
Increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing
~ 200,000 premature deaths per year in US (Caiazzo et al. Atmos Env 2013)
Globally 3.2 million deaths per year (~ 2 x the population of Philadelphia) and 76 million disability-adjusted life years (Lim et al 2010, Lancet, WHO Study)
Much our exposure occurs indoors, because, on average, we are indoors 90% of the time.

3. Analysis Scope OUTCOMES
Reductions in premature mortality from filtration interventions that decrease indoor exposures to particles from outdoor air
Costs of materials and energy of interventions
Economic benefits of the reduced premature mortality
EVALUATED
Nine filtration interventions
Three locations: Counties containing Los Angeles CA, Elizabeth NJ, Houston TX

4. Increase Filtration Time
Improve Filtration in HVAC Systems of Commercial and Institutional Buildings
Use Better Filter
Improve Filtration in Home Heating Central Forced Air Heating and Air Conditioning Systems
Use Better Filter
Increase Filtration Time
Use Portable Air Cleaners with Fans and High Efficiency Filters

5. Analysis Method-Mortality
Base Case Indoor PM2.5
Inter-
vention Case Reduction of PM2.5
Inhalation
Equiva-lent Reduction of Outdoor PM2.5
Fractional Mortality Reduction
Prevented Premature Deaths
Inter-vention Case Indoor PM2.5
Time-Activity Data, Breathing Rates
Concen-tration vs. Mortality Equation
Baseline Mortality, Population

6. Methods Economic Benefits and Costs
Annual Prevented Premature Deaths
$ Value of Premature Deaths
$8.4 x 106
Annual $ Benefit X =
Annual Incremental Cost of Better Filters
Annual Incremental HVAC Energy Cost +
Annual Intervention Cost =
Annualized Portable Air Cleaner Purchase Price
Annual Portable Air Cleaner Filter Replacement Costs
Annual Portable Air Cleaner Energy Costs + +

7. Overview of Methods – Other
Assumed interventions were applied in all homes with one family per building
Supplementary analysis assumed interventions were applied only in homes having residents with age ≥ 65
Modeled each season
Home ventilation rates, outdoor air PM2.5 concentrations, and baseline time of operation of central forced air fans varied among seasons
Sampled from distributions of model input parameter values
Sensitivity analysis considered low and high estimates of the mortality risk coefficient for PM2.5 and ± 25% changes in central estimates of other key model inputs

8. MERV Rating System for Filters
Standard
Minimum MERV
ASHRAE Residential 62.2 6*
ASHRAE Commercial 62.1 8*
*MERV 11 recommended in PM non-attainment areas
Source: El Orch et al. (2014) Building and Environment 74:

9. Baseline (Reference) Cases
BASELINE 1 Homes have central forced air (CFA) space conditioning systems with MERV 6 filters; Commercial and institutional buildings have HVAC systems with MERV 8 filters BASELINE 2 Homes have no central forced air (CFA) space conditioning systems; Commercial and institutional buildings have HVAC systems with MERV 8 filters

10. Interventions X X Intervention Code** No central forced air (CFA)
LE 30% 1b
LE 40% 2a
HE 30% 2b
HE 40% 3
HE INT 4
LE INT
PAC 5a 5b 6a 6b 7
NO CFA 8
COMM MERV 11 9
COMM MERV 13
No central forced air (CFA) X
Intermittent CFA operation
30% Time CFA operation
40% time CFA operation
MERV 6 CFA Filter
MERV 12 (effective MERV 9) CFA filter
MERV 8 commercial and institutional HVAC filters
MERV 11 commercial and institutional HVAC filters
MERV 13 commercial and institutional HVAC filters
Portable air cleaner (PAC) in home, CADR = 1 volume/hr X 

11. Reductions in Annual Mortality in LA
>
> 1000 prevented premature deaths per year
+FAN
+ FLT
+ PAC
+FAN
+FLT
+FAN
+ PAC
+PAC
+PAC
+FLT
+FLT
Comm
+FAN
++FLT
Comm

12. Reductions in Mortality in Houston
+FAN
+ FLT
+ PAC
+FAN
+FLT
+FAN
+ PAC
+PAC
+PAC
+FLT
+FLT
Comm
+FAN
++FLT
Comm

13. Intervention Costs Per Person in LA
+FAN
+ FLT
+ PAC
+FAN
+ PAC
+PAC
+PAC
+FAN
+FLT
+FAN
+FLT
Comm
++FLT
Comm
+FLT

14. Benefits Per Person in LA
+FAN
+ EFF
+ PAC
+FAN
+EFF
+FAN
+ PAC
+PAC
+PAC
+EFF
++EFF
Comm
+EFF
Comm
+FAN

15. Benefit to Cost Ratio in LA
+FLT
Comm
++FLT
Comm
+FAN
+FLT
+FAN
+ FLT
+ PAC
+FLT
+FAN
+ PAC
+PAC
+PAC
+FAN

16. Cost Per Prevented Premature Death in LA
+FAN
+FAN
+ FLT
+ PAC
+FAN
+ PAC
+FAN
+FLT
+PAC
+PAC
+FLT
+FLT
Comm
++FLT
Comm

17. What happens if we intervene only in the 24% to 30% of homes with elderly?
Intervention costs are decreased by 70% to 76%
Prevented premature deaths decrease by 30% or less
The estimated benefit – cost ratio increases by a factor of two to five

18. Summary of Findings
Largest estimated mortality reductions from interventions in homes
> 1000 prevented premature deaths per year in LA County
Among our selected interventions, the largest mortality reductions are from interventions that included continuously operating portable air cleaners in homes
Increasing operation time of home CFA system and improving filter efficiency reduced mortality much more than only increasing CFA operation or only increasing filter efficiency
Annual economic benefits per person were as high as ~ $2000
Estimated benefit cost ratios (BCRs) always exceeded unity
BCRs were 6 to 13 for interventions with portable air cleaners that most decreased premature mortality
BCRs were 74 to 133 for improvements in efficiency of filters in commercial and institutional buildings

19. Extrapolation To Interventions in All US Homes
Up to 64,000 prevented premature deaths per year
1.5 times the deaths from motor vehicle accidents
Up to $0.32 trillion in annual economic benefits

20. Using Filtration to Reduce Exposures to Outdoor Air Particles in Offices,
Net annual benefit of supply air filtration versus filter efficiency rating for office HVAC system with 100% OA Montgomery et al. Building and Envir. 2015
Current US Practice

21. Limitations Analysis did not estimate
Reductions in morbidity
Health benefits from reducing indoor concentrations of indoor- generated particles
Costs of control hardware needed to increase CFA system fan operation to 30% or 40% time
Seasonal calculations do not capture effects of diurnal and day to day variability in outdoor PM2.5, ventilation rates, home CFA system operation
We used a simple method to discount performance of portable air cleaners due to imperfect mixing of indoor air.

22. More Information
Fisk, WJ and Chan WR. Effectiveness and cost of reducing particle-related mortality with particle filtration. Indoor Air Journal (early view section of journal’s web site, DOI: /ina.12371)
See section on air cleaning at