美某些標榜臭氧殺菌、除臭的空氣清淨機機種，所刻意排放出的臭氧，正是一種主要的廢氣成分，對健康有所危害。美國加州空氣資源局（California Air Resources Board）日前對消費者發出上述警訊，提醒替聖誕假期採購禮品的頻眾，勿購買會排放出臭氧的空淨機。
加州空氣資源局警告：「此類臭氧製造機不僅在對淨化室內空氣無效，同時讓人們吸入臭氧也提高健康上的風險。建議大家別再使用臭氧製造機。」該局局長尼克斯（Mary Nichols）指出：「消費者在考慮購買空淨機時，應小心廣告的誤導，錯把廢氣生成機當成空淨機。」
所謂「臭氧空淨機」所釋出的臭氧，將使氣喘惡化、導致嚴重肺炎、減低肺功能、最後造成許多人因呼吸系统問題住院、急診室擠滿氣喘病人，並增加學生缺席率。
其中一家被資源局列入黑名單的Air-Zone已先於網站上公告警示文字：「因臭氧效果劇烈，製造機只適用於無人空間，請勿於有人的空間使用。本機內建定時器，消費者可設定機器在您回來前自行關閉。臭氧將於一個小時內消散。」
加州州長阿諾曾於2006年9月簽署2276號法案，針對市售此類產品進行規範以確保公眾健康，據此，加州空氣資源局應制定相關規定，限制是內空淨機的臭氧排出量。目前此項法規已於今年10月18日定案，在兩年後（2010年10月18日以前），所有在加州販售的產品都必須符合規範。
目前，空淨機已由州政府統一測試，確保釋出的臭氧未達有害程度。然而，空淨機經過認證實驗室測試還得花上兩年時間，在這段期間內，過度釋放臭氧的機種卻照樣販售。因此，在這段空窗期，加州空氣資源局建議大眾避免購買任何會釋放臭氧的家用或辦公空淨機，要避免室內空氣污染，最有效的方式是移除污染源、避免與排放源為伍，而促進新鮮空氣的流通，也會有所幫助。
對於仍想使用空淨機的民眾，則建議使用裝設高效率打摺式濾芯（或稱HEPA濾芯）或是不會釋出高濃度臭氧的靜電集塵式空淨機。
加州空氣資源局的消費指南網頁中，列舉了多項常見問題集以及「空淨機黑名單」，名單內販售種類包括家用、商用、車用以及個人使用的機種，提供民眾參考。
The California Air Resources Board has issued a consumer alert, advising holiday shoppers not to purchase air purifiers or air cleaning devices that intentionally generate ozone.
Some devices that are advertised as "air purifiers," air cleaners, or ozone generators purposely emit large amounts of ozone, the main component of smog.
"Not only are such ozone generators ineffective at cleaning indoor air, but breathing ozone poses serious health risks," warns the Air Resources Board, recommending that these ozone generators not be used.
"Consumers should take care when considering purchase of an air cleaning device," said ARB Chairman Mary Nichols, "Beware of misleading advertisements offering air purifiers that are simply indoor smog-making machines."
The devices can produce levels of ozone that can worsen asthma, cause serious lung inflammation, decrease lung function, and lead to hospitalization for respiratory conditions, emergency room visits for asthma, and increased school absences.
Air-Zone, one of the companies selling devices on the board's long don't buy list has a prominent warning on its website, "IMPORTANT NOTE: THIS OZONE GENERATOR IS MEANT FOR UNOCCUPIED ROOM USE ONLY. THIS MACHINE CANNOT EVER BE USED IN OCCUPIED ROOMS. IT IS FAR TOO STRONG. It has a built in timer so you can run the unit and have it automatically shut itself off long before you return. One hour later all the ozone will be gone."
Air-Zone, one of the companies selling devices on the board's long don't buy list has a prominent warning on its website, "IMPORTANT NOTE: THIS OZONE GENERATOR IS MEANT FOR UNOCCUPIED ROOM USE ONLY. THIS MACHINE CANNOT EVER BE USED IN OCCUPIED ROOMS. IT IS FAR TOO STRONG. It has a built in timer so you can run the unit and have it automatically shut itself off long before you return. One hour later all the ozone will be gone."
Recently, California regulated the sale of these devices to protect public health. California Assembly Bill 2276 (2006, Pavley), signed by Governor Arnold Schwarzenegger in September 2006, directed the Air Resources Board to develop and adopt a regulation to limit the amount of ozone emitted from indoor air cleaning devices.
The regulation became final on October 18, 2008, and all air cleaning devices sold in California must meet the requirements by October 18, 2010, the full compliance date.
Currently, air cleaners are being tested by the state to assure they do not emit harmful levels of ozone; however, testing of air cleaners by certified laboratories is expected to take up to two years. During this interim time period high ozone-emitting devices can still be sold.
For that reason, the Air Resources Board recommends consumers avoid the purchase of any air cleaner for home or office that intentionally emits ozone.
The best and most effective way to avoid indoor air pollution problems is to remove the sources of the pollution or prevent emissions to begin with, the board advises. Improving fresh-air ventilation is also helpful.
Those still wishing to use an air cleaner should look for models that use high-efficiency pleated filters, known as HEPA filters, or electrostatic precipitators that do not emit high amounts of ozone.
For guidance in selecting air cleaners, including ratings in Consumer Reports articles and ARB's fact sheet entitled "Air Cleaning Devices for the Home: Frequently Asked Questions," click here.
Click here for a list of air cleaners to avoid. The list includes air cleaners sold primarily for residential use, plus some for commercial, in-vehicle, and personal use.
