input question: Question: "What does PM in PM2.5 stand for?"  Context: "A dense wave of smog began in the Central and Eastern part of China on 2 December 2013 across a distance of around 1,200 kilometres (750 mi), including Tianjin, Hebei, Shandong, Jiangsu, Anhui, Shanghai and Zhejiang. A lack of cold air flow, combined with slow-moving air masses carrying industrial emissions, collected airborne pollutants to form a thick layer of smog over the region. The heavy smog heavily polluted central and southern Jiangsu Province, especially in and around Nanjing, with its AQI pollution Index at "severely polluted" for five straight days and "heavily polluted" for nine. On 3 December 2013, levels of PM2.5 particulate matter average over 943 micrograms per cubic metre, falling to over 338 micrograms per cubic metre on 4 December 2013. Between 3:00 pm, 3 December and 2:00pm, 4 December local time, several expressways from Nanjing to other Jiangsu cities were closed, stranding dozens of passenger buses in Zhongyangmen bus station. From 5 to 6 December, Nanjing issued a red alert for air pollution and closed down all kindergarten through middle schools. Children's Hospital outpatient services increased by 33 percent; general incidence of bronchitis, pneumonia, upper respiratory tract infections significantly increased. The smog dissipated 12 December. Officials blamed the dense pollution on lack of wind, automobile exhaust emissions under low air pressure, and coal-powered district heating system in North China region. Prevailing winds blew low-hanging air masses of factory emissions (mostly SO2) towards China's east coast."  Answer:???
output answer: particulate matter

input question: Question: "What happened during the 40th year of the 20th century?"  Context: "On 6 August 1940, Estonia was annexed by the Soviet Union as the Estonian SSR. The provisions in the Estonian constitution requiring a popular referendum to decide on joining a supra-national body were ignored. Instead the vote to join the Soviet Union was taken by those elected in the elections held the previous month. Additionally those who had failed to do their "political duty" of voting Estonia into the USSR, specifically those who had failed to have their passports stamped for voting, were condemned to death by Soviet tribunals. The repressions followed with the mass deportations carried out by the Soviets in Estonia on 14 June 1941. Many of the country's political and intellectual leaders were killed or deported to remote areas of the USSR by the Soviet authorities in 1940–1941. Repressive actions were also taken against thousands of ordinary people."  Answer:???
output answer: Estonia was annexed by the Soviet Union as the Estonian SSR

input question: Question: "The Persian Revolt led to which person taking over Media?"  Context: "In 550 BC, Cyrus the Great, son of Mandane and Cambyses I, took over the Median Empire, and founded the Achaemenid Empire by unifying other city states. The conquest of Media was a result of what is called the Persian Revolt. The brouhaha was initially triggered by the actions of the Median ruler Astyages, and was quickly spread to other provinces, as they allied with the Persians. Later conquests under Cyrus and his successors expanded the empire to include Lydia, Babylon, Egypt, parts of the Balkans and Eastern Europe proper, as well as the lands to the west of the Indus and Oxus rivers."  Answer:???
output answer: Cyrus the Great

input question: Question: "It can be inferred that red glass objects in the 12th century, like goblets or chandeliers, got their color from what?"  Context: "Red was the color of the banner of the Byzantine emperors. In Western Europe, Emperor Charlemagne painted his palace red as a very visible symbol of his authority, and wore red shoes at his coronation. Kings, princes and, beginning in 1295, Roman Catholic cardinals began to wear red costumes. When Abbe Suger rebuilt Saint Denis Basilica outside Paris in the early 12th century, he added stained glass windows colored blue cobalt glass and red glass tinted with copper. Together they flooded the basilica with a mystical light. Soon stained glass windows were being added to cathedrals all across France, England and Germany. In Medieval painting red was used to attract attention to the most important figures; both Christ and the Virgin Mary were commonly painted wearing red mantles."  Answer:???
output answer:
copper