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

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.

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

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

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

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 + +

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

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: 106 - 118

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

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 

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

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

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

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

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

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

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

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

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

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

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.

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: 10.1111/ina.12371) See section on air cleaning at https://iaqscience.lbl.gov