Tree Study Criticized; Researcher Defends It

Your article raises more questions than it answers. Why, since plants are our greatest source of clean air, did it not include what the trees produce over a 24-hour period instead of only in sunlight. Drawing conclusions without measuring the air cleaning properties of the same trees seems flawed. The investigator may have been out in the smog too long.

I find it unfortunate that the study only looks at the hydrocarbons produced by certain trees in sunlight, in a sterile air environment, enclosed in a plastic bag.

Even the lay person understands that trees will do everything in their power to survive and I suspect that the trees will produce what they need to survive when there is sunlight or darkness. The broad-leaf deciduous trees in the experiment produce the highest hydrocarbons. Is it also possible they produce the greatest benefits in cleaning the air during the dark hours?

Placing a plastic bag over a human being and measuring the rates and actions taken to survive as normal behavior would be inappropriate. Gasping for air would not I believe represent normal breathing characteristics for the subject. Measuring the increases and decreases in a normal environment that had hydrocarbons and other properties over the full 24 hours and all four seasons of the year would be a more valuable comparison.

SAUL H. KAY

Encino