The impression they gave was that they didn't want foreigners to come". According to the Beijing Olympic Organising Committee (BOCOG), the 6.8 million tickets to the Games were sold out. The prevalence of empty seats at many events caused journalists and visitors to be suspicious about these claims. Beijing Olympic organisers were said to have given some 2.7 million tickets to officials and corporate sponsors, many of whom did not attend the events. A mainland journal suggested that the day-tickets without right of re-entry was also part of the problem. In one instance, people in the audience left the stadium after the Chinese women's volleyball match, but they were not allowed back when they found out there was another game. A senior BOCOG official expressed concern about the empty seats, saying that the hot, humid weather could have caused the poor turnout. Officials admitted to bussing in locals or "cheerleaders" to fill seats. The empty seats angered athletes of countries outside China, who had been told that 80 percent of tickets had been reserved for the Chinese. Despite early warnings published by "The Guardian" and efforts by official ticketing coordinators, more than $6 million in fraudulent tickets were sold by an illegitimate online ticket broker. Poor-quality air in China contributes to the death of about 400,000 Chinese annually. Ozone and fine particulate matter—bits of carbon, sulfates, and industrial by-products— were the two biggest pollution threats to the athletes in 2008. When high ozone levels are present, lungs are not able to absorb as much oxygen, causing coughing, wheezing, or headaches.