UNIT E D ST ATES EN VI RONM ENT A L PROTE C TI ON A G ENCY

WASHINGTON D.C. 20460

OFFICE OF T H E ADMINISTRAT OR

SCIENCE AD VISORY BOARD Decem ber 6, 2004

EPA- COUNCIL -LTR-05-001

The Honorable Michael O. Leavitt

Adm i nistra tor
U.S. Environm ental Protection Agency 1200 Pennsylvania Avenue, N.W

. Washington, D.C. 20460

SUBJECT: Advisory Council on Clean Air Compliance A n alysis Response to Agency Request on Cessation L a g

Dear Adm i nistr a to r Leav itt:

In a letter of August 11, 2004, the Office of Air and Radiation and Office of Policy,

Econom ics and Innovation jointly as ked the Health Effects Subcomm ittee (H ES) of the Advisory

Council on Clean Air C o m p liance Analysis to comment on an EPA proposal. This proposal, developed in collaboration with OMB, concerns the cessation lag of PM 2. 5 . The cessation lag is

def i ned as th e tim e patte r n of reductio ns in risk s o f m o rtality that would b e expected a f ter a
decrease in am bient particulate m a tter sm aller than 2.5 μm in aerodynam i c diam eter, i.e. PM 2. 5

. The letter requested the Council’ s S ubcomm ittee to cons ider whether a p r oposed lag structure is generally consistent with our recommendations re garding a previous charge question on this

issue.

Our previou s comm ents on this issue noted tha t b ecause som e fraction of the m o rtality

risk as sociated with PM 2. 5 is the result of long-term exposur es and disease pr ocesses such as chronic resp iratory disease and can cer, the reduction in m o rtality risk th at occurs when exposures are reduced m a y take several years to be fully realized. The EPA described a proposed lag

structure that would allo cate 20% of the benefits in the firs t year, a further 50% equally divided in the years 2 through 5, and the final 30% equally divided in the years 6 through 20. While we believe this proposal is broadly consistent with our recomm e nda tions, and preferable to the 5- year distributed lag used earlier , we would suggest a slight m odi fication to this proposal. W e have rev i ewed newly av ailab l e ev idence on this i ssue and con s idered seve ral intervention studies

exam ining reductions in exposure to either air pollution or from direct sm oking. ( See

attachm e nt.)

W h ile ther e is still considerable unce r ta in ty about the cessation lag, the air pollution evidence is genera lly su ggestiv e of greater im pacts in the first y ear relative to the p r o posed lagstructure in question. In fact, som e recent ab stra cts suggest that substantial benefits m i ght occur in the first year. Therefore, the Adviso ry Council on Clean Air Com p liance Analysis

recomm ends that EPA use a prim ary case where 30% of the mortality reductions occur in the first year, 50% occur equally in years 2 thr ough 5, and the remaining 20% occur equally over years 6 through 20.

These proposed changes to the cessation lag (both the EPA proposal and the HES

recomm ended m odification) do not change the estim at es of total m o rtality reductions expected as

a result of reductions in PM 2. 5 , but they both represent changes in th e estim ated tim ing of the expected m o rtality reductions. The HES recognizes that m easures of health ben e fits in physical

term s are no t the final step in benefit-cost an alys is, where all benefits need to be valued. The

tim e profile assum e d for health benefits m a y have im plications for “net present value” calculations. However, this final step of econo m i c valuation does not li e within the scope of expertise of the HES. The charge to the HES on this m a tter s p ecif i ca lly c oncerns th e patte rn of health benefits in physical term s, so we lim it our comments to this question.

We also urg e EPA to: (1 ) review and keep abre as t of the em erging liter a tu re in this a r e a ; (2) prov ide the best av ailable ju stif ic ation f o r th e lag structu r e they use; a nd (3) strongly consider conducting sensitivity analyses of other possible lag structures. EPA should also consider using

sm oothed distributions.

W ith regard to the suggestion to review e m er ging literature, it shoul d be noted that, in

addition to the litera ture f r om PM interventi on studies, inform ation from the sm oking cessation

literature is considered v e ry re levan t to the PM /mortality cess a ti on lag qu estion. Therefore, we

recomm end that EPA co nduct a sys t em atic review of the literature on the tim e course of health benefits following cessation of activ e and passiv e sm oking to better acco unt for this potentially

useful inform ation.

S i n c e r e l y
,

/ s / / s /

Trudy Cam e ron, Ph.D. Bart Ostro, Ph.D.

C h a i r C h a i r Advisory Council on Clean Air Compliance A n alysis Health Effects Subcommittee

Attachm e nt:

Studies Co nsidered by HES on PM-Mortality Cessation Lag

2

### Studies Considered by the Health Effects Subcommittee

on the PM-Mortality Cessation Lag

Clancy, L., Goodm a n, P., Sinclair, H ., and Dock ery, D.W

. (2002). Effect of Air-Pollution Control on Death Rates in Dublin, Ireland: An Intervention Study. The Lancet 360 : 1210-1214.

Fry, C., Hoelscher, B., C y rys, J., W j st, M., W i ch m a nn, H. and Heinrich, J. (2003). A ssociation of Lung Function with Declining Am bient Air Pollution. Envir onmental Health Perspectives 111 : 383-387.

Heinrich, J. Hoelscher, B., Frye, C., Meyer, I. P i tz, M. Cyrys, J., W j st, M. Neas, L., W i chm a nn, H.E. (July 2002). Im proved Air Quality in Reun ified Germ a ny and Decreases in Respiratory Sym p tom s

. Epidemiolog y 13 : 394-401.

Heinrich, J., Hoelscher, B., and W i chm a nn, H.E. (2000). Declin e of Am bi ent Air Pollution and Respira t ory Sym p tom s in Children. American Journal of Respiratory Critical Care

Medicine 161 : 1930-1936.

Hurley, Fintan. (2004). Does Re ducing Air Pollution Really Lead to Im provem e nts in Health? Excerpt from a report entitled Evaluation of the Air Quality Strategy prepared for the Department for Environment, Food and Rural Affairs in the United Kingdom . The full report will be published in the com i ng m onths at http://www.defra.gov/uk

.

Lan, Q., Chapm a n, R.S., Schreinem achers, D.M., Tian, L., and He, X. (2002). Household Stove

Im prove m e nt and Risk of Lung Canc er in Xuanwei, China. Journal of the National

Cancer Institute 94 : 826-836.

Leksell, Ing e m a r and Rabl, Ari. (200 1). Ai r Pollution and M o rta lity : Quantif ica tion and

Valuation of Years of Life Lost. Risk Analysis 21 : 843-857.

Roosli, M., Kunzli, N. and Braun-Fahrlander, C. (2004). Use of Air Pollution “InterventionType” Studies in Health Risk Assessm e nt. Abstract presented at the 16 th Conference of the International Society fo r Environmental Epidemiology , August 1 – 4, 2004.

Schwartz, Joel and Laden, Franci ne. (2004). Dose, Tim e and Death: Association with PM2.5 in Cohort Study. Presentation to 16 th Conference of the International Society for Environmental Epidemiology , August 1 – 4, 2004.

3NOTICE

This report has been written as part of the activities of the EPA Advisory Council on Clean Air Compliance Analysis (Council), a public advisory committee providing extramural

scientific information and advice to the Admini strator and other official s of the Environmental Protection Agency. The Council is structured to provide balanced, expert assessment of scientific matters related to problems facing the Agency. This report has not been reviewed for approval by the Agency and, hence, the contents of this report do not necessarily represent the views and policies of the Environmental Protec tion Agency, nor of other agencies in the Executive Branch of the Federal government, nor does mention of trade names or commercial products constitute a recommendation for use. Reports of the EPA Council are posted on the

EPA website at: http://www.epa.gov/sab

.

### U.S. Environmental Protection Agency Advisory Council on Clean Air Compli ance Anal ysis

COUNCI L

CHAIR Dr. Trudy Ann Cameron , University of Oregon, Eugene, OR

Also Mem b er: Science Advisory Board

MEMBERS

Dr. David T. Allen , University of Texas, Austin, TX

Dr. Dallas Burtraw , Resources for the Future, Washington, DC

Ms. Lauraine Chestnut , Stratus Consulting Inc., Boulder, CO

Dr. Charles T. Driscoll, Jr. , Syracus e University , Syracuse, NY

Dr. Wayne Gray , Clark University, Worcester, MA

Dr. James K. Hammitt , Harvard U n iversity, B o ston, MA

Dr. F. Reed Johnson , Research Triangle Ins t itute, Research Triangle Park, NC

Dr. Katherine Kie l , College of the Holy Cross, Worcester, MA

Dr. Nino Kuen z l i , University of Southern California, Los Angeles, CA

Dr. Virginia McConnell , Resources for the Future, W a shington, DC

Dr. Bart Ostro , Californ i a Office of Environm ental He alth H azard Assessm e nt, Oakland, CA

Dr. V. Kerry Smith , North Caro lina State Unive r sity, Raleigh

, NC

Dr. Chris Walcek , State University of New York, Albany, NY

SCIENCE ADVISORY BOARD STAFF Dr. Holly S t allw orth , Washington, DC

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### U.S. Environmental Protection Agency Advisory Council on Clean Air Compli ance Anal ysis

Health Effects Subcommittee

CHAIR

Dr. Bart Ostro , Californ i a Office of Environm ental He alth H azard Assessm e nt, Oakland, CA

MEMBERS Mr. John Fintan Hurley , Institute of Occupational Me dicine (IOM), Edinburgh, United Kingdom

Dr. Patric k Kinney , Colu m b ia University, New York, NY

Dr. Michael Kle inman , University o f Calif ornia, Irvine, Irv in e, CA

Dr. Nino Kuen z l i , University of Southern California, Los Angeles, CA

Dr. Morton Lippmann , New York University School of Medicine, Tuxedo, NY

Dr. Rebecca Parkin , T h e George Washington Un iversity, Washington, DC

Mem b er: Science Advis o ry Board

SCIENCE ADVISORY BOARD STAFF Dr. Holly S t allw orth , Washington, DC

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