Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Lung Disease & Respiratory Health Center

Font Size

Windows a Culprit in Air Pollution?

In Sunlight, Grime on Windows May Recirculate Smog Chemical Back Into the Air
WebMD Health News
Reviewed by Louise Chang, MD

May 11, 2007 -- Grime on windows may contribute to air pollution, a Canadian study suggests.

Scientists from the University of Toronto did several lab tests on window grime, which they call "urban organic films."

Window grime can soak up an inactive version of the smog chemical nitric acid, note the researchers, who included D.J. Donaldson, PhD, of the University of Toronto's chemistry department and department of physical and environmental sciences.

In a lab, Donaldson's team concocted a solution like window grime and smeared it on a microscope slide.

The scientists observed how the window grime's chemistry changed when exposed to light in a series of lab tests.

Light caused a chemical change in the nitric acid, breaking it down and gradually releasing the mixture into the air.

If the same thing happens outside the lab, it could mean that window grime, in sunlight, recycles smog-related chemicals.

The findings are scheduled for publication in the June 15 edition of the journal Environmental Science & Technology.

Today on WebMD

man coughing
You may not even know you have it.
blood clot
Signs of this potentially fatal complication.
man coughing
When a cold becomes bronchitis.
human lungs
Causes behind painful breathing, fluid buildup.

chest x-ray
Bronchitis Overview
Copd Myth Fact Quiz
Energy Boosting Foods

woman coughing
Lung xray and caduceus