BEIJING — Membership in the upper ranks of the Chinese Communist Party has always had a few undeniable advantages. There are the state-supplied luxury sedans, special schools for the young ones and even organic produce grown on well-guarded, government-run farms. When they fall ill, senior leaders can check into 301 Military Hospital, long considered the capital’s premier medical institution.

But even in their most addled moments of envy, ordinary Beijingers could take some comfort in the knowledge that the soupy air they breathe on especially polluted days also finds its way into the lungs of the privileged and pampered.

Such assumptions, it seems, are not entirely accurate.

As it turns out, the homes and offices of many top leaders are filtered by high-end devices, at least according to a Chinese company, the Broad Group, which has been promoting its air-purifying machines in advertisements that highlight their ubiquity in places where many officials work and live.

The company’s vice president, Zhang Zhong, said there were more than 200 purifiers scattered throughout Great Hall of the People, the office of China’s president, Hu Jintao, and Zhongnanhai, the walled compound for senior leaders and their families. “Creating clean, healthy air for our national leaders is a blessing to the people,” boasts the company’s promotional material, which includes endorsements from a variety of government and corporate leaders, among them Long Yongtu, a top economic official who insists on bringing the device along for car rides and hotel stays. “Breathing clean air is a basic human need,” he says in a testimonial.